42 



HANDBOOK OF PHOTOGRAPHY 



(Fig. 15) 

 (Fig. 12) 

 (Fig. 14) 

 (Fig. 14) 

 (Fig. 15) 



Table III. — -Symmetrical Anastigmats 



Manufacturer Lens System 



Tivo Triplets 



Busoh Leukar ? 



Goerz Dagor -|- — -f- ; (Fig. 12) 



Gundlach Perigraphic ? 



Rodenstock Eikonar ? 



Schneider Angulon — 



Schneider Symmar -f- — -\- 



Steinheil Orthostigmat + 



Voigtlander Collinear + 



Watson Holostigmat — 



Zeiss Convertible Protar) 



Zeiss Ortho Protar / ' ' ^ ^^• 



Zeiss Triple Protar H + : (Fij 



Two Quadruplets 



Beck Bystigmar - + + — : (Fig. 13) 



Goerz Pantar ^ + + : (Fig. 18) 



Reichert Combinar + H + : (Fig. 16) 



Rietzschel Linear + — + — : (Fig. 17) 



Simon Octanar + + — + : (Fig. 16) 



Zeiss Double Protar h -\ : (Fig. 13) 



Tv^o Quintuplets 



Goerz Convertible Anastigmat Series II — + — + — : (Fig. 19) 



Turner-Reich lens \- H : (Fig. 20) 



15) 

 12) 



These completely cemented symmetrical lenses do not generally exceed //6.3 

 in aperture, with some exceptions up to //4.5, but they cover a wide field of as much as 

 90° in some cases. Some of the triplets are convertible but generally only at reduced 

 aperture. In some cases a front lens of one type is convertible with a back lens of a 

 different type such as the Polyplast of Dr. Stable (Fig. 21). 



Fig. 21.— Polyplast 

 convertible lens. 



Fig. 22. — Meyer Plasmat, //4. 



The convertible lens has largely disappeared from amateur use with the advent of 

 fixed-lens hand cameras. To use a convertible lens adequately, a tripod and focusing 

 screen are really necessary. 



In recent j^ears, considerable improvements have been made bj' separating one or 

 more of the lenses in these symmetrical types, and in some cases departing from strict 



24. — Schneider Ortho- 

 Angulon. 



Fig. 25. — Meyer Kino-Plas- 

 mat, //1. 5. 



symmetry. For example, in the Meyer Plasmat //4 (Fig. 22), the two lenses nearest 

 the stop in the Goerz Dagor have been detached, the same type of construction being 

 adopted in the Ross //4 wide-angle Xpres, the Schulze Euryplan //6, the Busch 



